Playing the filth card

Channel 4 is making a show which encourages participants to break sexual taboos.

Called Sex Rules, the programme is billed as an examination of sexual experiences such as threesomes and casual encounters with strangers.

In an alarming sign that the station is reverting to its sex-filled past in the pursuit of ratings, Channel 4 is said to be urging those appearing to 'push the boundaries' for the six-part series.

One source said: 'This takes things a step beyond Big Brother.

'There are different sections. One is about people who just use friends for sex.

'Another is called Shag Express, which features people who go out just to have sex with strangers. Another is about threesomes. It's really pushing the limits.'

The source added: 'Has Channel 4 really thought about the consequences of asking people to come forward to promote this kind of behaviour?'

Although participants will not be seen having intercourse, there will be graphic descriptions of their experiences.

The station is still looking to recruit people to take part in the programme, which is due to be broadcast next year, and admits finding them will be difficult.

The series is one of the first to be given the green light under new chief executive Mark Thompson - formerly BBC director of television.

According to insiders, Mr Thompson wants to 'explore the rules young people have for sex in the 21st century'. The series has been ordered in the midst of a radical overhaul as the station clears out failing shows and cuts staff to reduce costs and boost ratings.

The new chief aims to start the schedule from scratch from 2004 to compete with a stronger BBC and Channel 5. Part of his plan is to try to attract a younger audience.

Mr Thompson, who joined from the BBC this spring, said earlier this month that he is looking for 'braver programming'.

The station also had plans to make a show called Camper Van which followed eight gay men as they toured a foreign country in a Volkswagen camper van in pursuit of sex. It decided, however, that it would be too controversial.

Although Channel 4 is a commercial station, a condition of its licence, granted by the Government, was that it should 'foster the new and experimental in television'.

However, some critics believe that Sex Rules goes too far.

John Beyer, of pressure group Mediawatch, said: 'I hope this programme carries a Government health warning about sexually transmitted diseases. It's all very well doing this but what about the consequences?

'I hope Channel 4 will broadcast a warning about the risks in the same way they broadcast warnings about strong language.'